Electric-railway trolley



(No Model.) D FIELD 2 Sheets-Sheet 1. ELECTRIC RAILWAY TROLLEY.

1 Patented Nov.

(No Model.) 2 Sheets-Sheet 2.

S. D. FIELD.

ELECTRIC RAILWAY TROLLEY. No. 508,539. Patented Nov. 14,1893.

I UNITED STATES PATENT OFFICE.

STEPHEN D. FIELD, OF STOCKBRIDGE, MASSACHUSETTS.

ELECTRlC-RAIILWAY 'l'ROhLEY.

SPECIFICATION forming part of Letters Patent No. 508,539, dated November 14, 1893. Application filed March 2, 1891. Serial No. 383,385. (No model.)

To all whom it may concern:

Be it known that I, STEPHEN D. FIELD, of

Stockbridge, in the countyof Berkshire and State of Massachusetts, haveinvented certain new and useful Improvements in Electric;

I Railway Systems; and I do herebydeclare that the following specification, taken in con,- nection with the drawingsfurnished and formmg a part of the same, is a clear, true,-and

complete description of the several features of my invention.

the service conductor, in electric railway systems.

The invention consists, in the combination and arrangement of devices substantially as hereinafter more fully described and claimed.

In the drawings which form part of this specification, Figure 1, is a transverse section through the trolley and main conductor. Fig. 2, is a side elevation of the same, these figures illustrating an embodiment of the main features of my invention, in a comparatively simple form. Fig. 3, is a transverse section, through the trolley and main conductor, showing a modification of the circuit arrangements, and embodying my invention in a more complex form. v

The main conductor 1, being of iron or steel, will usually be of considerable, diameter, in order to carry the required current at proper efiiciency.

The trolley, Figs. 1 and 2, is constructed as follows: I take a disk, 2, of iron or steel, and having a projecting core, or shaft 3, on which I fix another disk of 'iron, or steel, 4, and 1 prefer to dish the two disks, toward each other, and hold them in fixed relation against springing of the metal, by means of the nonmagnetic ring 5. The peripheries, or contact faces of the two disks, 2, and 4, are so separated and shaped, as to fit or conform to, the cross section of the main conductor 1, and these disks, are to be of considerable thickness, so as to be capable of becoming strongly magnetized. The central core,o'r shaft 3, extends through both the disks '2and 4c, and outside of them, forms the journals 6 and 7 respectively. Before placing disk, 4, in position on the central core or shaft 3, I place upon the latter, a helix 8, which I prefer to make of comparatively small insulated wire,

as it is to be used as a shunt. Supported by 5 .the journals 6, and 7, is a two part yoke, or

haiger, 9,10, the parts being united at 11, and there forming a point of attachment for the flexible conductor, which is intended to carry the main current, from stationary conductor 1, tothe electric motor on the moving car'or other vehicle. One end of the coil, 8, is connected directly to one of the disks, as 2,

t v v and the other end is connected to an insulated This invention relates to novelmeansfor" 1 rod, or, pin 12, which projects out centrally establishing a reliable running contact with j from the journal ,7, of the core 3. Upon the part 10, of the hanger, but insulated therefrom, I arrange a contact spring 13, which bears upon theendof the pin, 12, as shown. From this contact spring, 13, a flexible conductor of any suitable character, is led down,

either separately, or in company with the flexible main conductor, and is then connected, throngh suitable resistance to the return conductor, whether the same be the rails, or a separate conductor "or the purpose. A disk or plate 14, is placed upon the end of journal 7, as a precaution to prevent oil, or dirt, from the bearing reaching the contacts, formed by pin 12, and spring 13.

- From the foregoing, it will be seen, that current is led directly over main conductor 1, through the coil 8, and thence through suitable resistance, if necessary, to the return conductor, the circuit thus formed, being in shunt to the motor, on the car, or other vehicle. Obviously, a safety fuse may be employed in this circuit, or several'of them if desired. This current is so calculated, or proportioned, as to powerfully magnetize the core 3, whence the magnetism is developed on the adjoining rims of the disks 2 and 4, which in this case, will be of opposite polarity and the main conductor 1, constitutes an armature, joining the two poles. Hence, powerful attraction will be set up, sufficient to safely support a very much heavier trolley, than will ever be called into requisition. The

adhesive effect obtainable by this arrangeto the rotation of the disks, as the trolley is drawn along the conductor 1, and this retardation, will be just about enough, to prevent overrunning of the trolley, due to irregularities of speed, when the conducting cord, is employed as the means of propelling the trolley.

I prefer to make the trolley of steel, for the reason that its residual magnetism, will prevent the falling of the trolley during the absence of current from the main conductor 1, should such a contingency occur.

In some cases, what is known as compound winding, or in other words, two co-operating energizing coils, may be successfully employed on the core, 3, which forms the-shaft of the magnetically adhesive trolley. This would be of particular benefit, in those cases where great, and irregular drops of potential are experienced on the main conductor 1. Such compound winding, would consist in mounting a few turns of coarse wire on the core 3, in addition to the fine wire coil, already described, and connecting such coarse wire coil, in suitable manner directly into the motor circuit. These two exciting coils, s'o connected, compensate for any loss of magnetic energy in the trolley, due to a weakening of the shunt by an abnormally low resistance in the motor, such as is experienced in starting from a stateof rest,under a heavy load. Such modification, is fully illustrated by Fig. 3, which difiers from the construction shown in Figs. 1 and 2 only in the following particulars: The core 3, has wound upon it a heavy Wire 15, which constitutes the series circuit of the compound winding, and outside this, is wound the shunt coil 8, whose connections are the same as described in re spect of the form shown at Figs. 1 and 2. In order to make the series Winding eflective, I place the insulating sleeves 16 and 17 around the bearings for the journals 6, and 7, and then connect one end of the coil 15, to the metal of one of the disks 2, or 4, and the other end of the said coil, is carried out through an insulating sleeve, so as to project beyond the journal 6. A bracket 18, attached directly through the coil 15, exerting a certain magnetizing effect on the core 3, and thence passes into brush 19, bracket 18, yoke 9, whence it goes ,directly to the motor on the car, and to the return conductor. Another portion of the current, passes from the trolley disks through the shunt coil 8, and thence by the conductor 12, into the spring 13,whence it goes direct to the return circuit, constituting as before, a shunt around the motor.

In cases where the supply or working conductor 1, is placed over the car, or other vehicle, it will be apparent that there will be none of the strain. which is due to the thrust of the springs, usually employed to maintain contact. It will also be apparent, that a trolley of the above character, or a modification thereof, based on-the same principle, may be successfully employed, where the main conductor 1, is placed in a conduit beneath the car.

I claim as my invention- 1. A magnetically adhesive trolley for electric railways, embodying a wheel com posed of magnetic metahand carrying two co-operating exciting coils, both adapted to be energiz'ed from a main conductor, but having one of said coils adapted to be connected with a return conductor and outside of the inotor circuit, and the other adapted for connection with the motor circuit.

2. For use on electric railways, a magnetically adhesive trolley having a magnetized wheel, provided with tread, or contact faces which are separated by a space laterally conforming to the cross section of a portion of the stationary or line conductor, with which the trolley is to operate in rolling contact.

STEPHEN D. FIELD.

Wi tn esses:

FREDK. A. Home, GEO. SEYMOUR. 

